The present invention relates to testing of a radio frequency (RF) data packet signal transceiver, and in particular, to testing such a device having multiple transmitters and receivers capable of simultaneous operations.
Many of today's electronic devices use wireless signal technologies for both connectivity and communications purposes. Because wireless devices transmit and receive electromagnetic energy, and because two or more wireless devices have the potential of interfering with the operations of one another by virtue of their signal frequencies and power spectral densities, these devices and their wireless signal technologies must adhere to various wireless signal technology standard specifications.
When designing such wireless devices, engineers take extra care to ensure that such devices will meet or exceed each of their included wireless signal technology prescribed standard-based specifications. Furthermore, when these devices are later being manufactured in quantity, they are tested to ensure that manufacturing defects will not cause improper operation, including their adherence to the included wireless signal technology standard-based specifications.
For testing these devices following their manufacture and assembly, current wireless device test systems typically employ testing subsystems for providing test signals to each device under test (DUT) and analyzing signals received from each DUT. Some subsystems (often referred to as “testers”) include one or more vector signal generators (VSG) for providing the source, or test, signals to be transmitted to the DUT, and one or more vector signal analyzers (VSA) for analyzing signals produced by the DUT. The production of test signals by a VSG and signal analysis performed by a VSA are generally programmable (e.g., through use of an internal programmable controller or an external programmable controller such as a personal computer) so as to allow each to be used for testing a variety of devices for adherence to a variety of wireless signal technology standards with differing frequency ranges, bandwidths and signal modulation characteristics.
Testing of wireless devices typically involves testing of a their receiving and transmitting subsystems. The tester will typically send a prescribed sequence of test data packet signals to a DUT, e.g., using different frequencies, power levels, and/or modulation technologies, to determine if the DUT receiving subsystem is operating properly. Similarly, the DUT will send test data packet signals at a variety of frequencies, power levels, and/or modulation technologies to determine if the DUT transmitting subsystem is operating properly.
Such wireless devices are increasingly supporting simultaneous operations of multiple transmitters, multiple receivers and/or both a transmitter and a receiver in the same or different signal bands, often using a single integrated circuit (IC) component within the device for performing those concurrent operations. From a testing perspective, these simultaneous operations pose new potential device performance problems that must be tested during manufacture to identify possible defects. For example, when two transmitters are operating simultaneously, power demand on the system power supply increases and can cause “pushing” or “pulling” of the operating frequencies of voltage controlled oscillators (VCOs) providing the carrier signal(s) and/or frequency up-conversion or down-conversion signal(s). Such increased power demand can also limit or reduce the power of the transmitted signal(s).
Also, in the case where one transceiver is receiving while a second transceiver in the same IC is transmitting, the transmitted signal can cause blocking in the receiver, particularly if using radiated (wireless) rather than conducted (wired) signal conveyance. The transmitted signal can also affect power supply voltage levels enough to pull the frequency of the VCO cause signal gain changes within the receiver.
Accordingly, it would be desirable to have techniques enabling reliable testing of wireless devices with multiple RF signal transmitters and receivers designed for simultaneous operations of their multiple transmitters, multiple receivers and/or both a transmitter and a receiver.